History

Royal Ontario Museum Burgess Shale Expeditions
(1975-ongoing)

In 1975, the Royal Ontario Museum became the fourth major institution to conduct active field work and research on the Burgess Shale. That 1975 season marked the beginning of the most extensive campaigns of field work in the history of the Burgess Shale, dwarfing all previous expeditions combined - not only in the number of field seasons and total number of days spent in the field, but also in the discovery of new fossil sites and the number of specimens collected.

The result of those expeditions is the ROM's mammoth collection of more than 150,000 Burgess Shale fossils encompassing about 200 described species. Most of these fossils were collected layer by layer in several quarries in the area between Wapta Mountain and Mount Field (informally known today as Fossil Ridge). Others came from localities tens of kilometres away from the type localities. These specimens, carefully stored and catalogued, represent a treasure trove for scientists and provide material for research projects ranging from taphonomy (i.e., preservation of fossils) and taxonomy (i.e., description of new species or revision of others) to evolutionary biology, as well as paleoecological and paleoenvironmental studies.

Research on the Burgess Shale continues today, with many exciting discoveries coming both from the field and the study of the existing collections.

Background

Desmond Collins, who left the Natural History Museum in London to join the ROM in 1968, led the first eighteen ROM field expeditions (between 1975 and 2000) - following in the tradition of the Smithsonian Institution (1909-1924), Harvard University (1930), and the Geological Survey of Canada (1966-1967). Collins had no idea in 1975 that this first expedition would not only radically transform his career, but greatly expand our knowledge of Cambrian life. When he began, Collins had no previous experience in the study of Burgess Shale fossils: his first visit to the site was a matter of serendipity.

Desmond Collins first visited the Walcott Quarry in 1972 during a one-day field excursion, part of the International Geological Congress held that year in Montreal. The excursion included Harry Whittington, James Aitken, and William Fritz - three key members of the previous GSC (Geological Survey of Canada) expeditions to the site in 1966-1967. During this short visit, Collins (whose area of expertise at the time was fossil cephalopods) was particularly impressed by the sheer number of fossils still scattered along the talus slopes after previous expeditions to the two existing quarries on Fossil Ridge (the Raymond Quarry and Walcott Quarry).

The First Expedition (1975)

Goal: Display Specimens for Canada

Collins' first visit also happened to coincide with a planned new gallery on Invertebrate Paleontology at the Royal Ontario Museum (a gallery that opened in 1977, but has since been replaced). He quickly realized the potential the discarded fossils from the Burgess Shale represented for the new gallery. The few specimens from the Walcott Quarry in the ROM collection at the time had been sent to the museum by Walcott himself decades earlier, but were not particularly suitable for an exhibit.

One of the arguments Collins made in favour of the first ROM collecting expedition was the fact that, in the early 1970s, there was no permanent display of Burgess Shale fossils in Canada. Today, the Royal Ontario Museum has the world's largest collection of Burgess Shale fossils with more than 150,000 specimens. But Collins had no plan to study the Burgess Shale in depth when he formally approached Parks Canada for permission to collect fossils for display … that would only come later.

Despite several requests from Desmond Collins, Parks Canada refused to allow excavations in 1975. Instead, the nine members of the ROM team would only be allowed to collect loose rocks (talus) below the Walcott and Raymond Quarries. Many of these rocks were chunks of shale that had been dug out and discarded by earlier expeditions. In addition to specimens for an upcoming ROM gallery, Parks Canada requested that the ROM team collect duplicates of common species to be used in teaching at universities and museums across Canada (including for Parks Canada itself).

The ROM 1975 crew. From left to right, front row: David Rudkin; Bruce Haugh; Chandler Rowell; Bob Barnett. Back row: Rod Fuller; Russ Barrows; Huibert Sabelis; Desmond Collins. (Harish Verma was part of the team but is not in the picture).

Despite poor weather conditions and the prohibition against excavations, the ROM team collected more than 8,000 fossils over eight weeks in the field. Most came from talus slopes below the Walcott Quarry and a smaller collection came from the Trilobite Beds on Mount Stephen. But the ROM team also discovered many specimens of the small arthropod Marrella splendens in Walcott's camp just below Burgess Pass. These fossils were found in piles of split shale that had been left behind in the camp.

The team also discovered a number of artifacts (tinware, bottles) left at the camp by Walcott at the end of his expeditions.

Back in Toronto, technician David Rudkin faced the daunting task of creating sets of duplicate specimens to be distributed to museums and universities – while keeping enough good display specimens for the ROM gallery. The ROM would send about 2,000 fossils from the 1975 collection (representing dozens of species) to more than 20 institutions across Canada. Perhaps more importantly, these early collections helped shift the focus of subsequent expeditions to new research.

Sorting the 1975 Burgess Shale collection back in Toronto at the Royal Ontario Museum.

Many surprises awaited the ROM crew in 1975. While scouring the slopes they found a new species, quickly dubbed the
"goose barnacle" (eventually described by Collins and Rudkin as Priscansermarinus barnetti).
The team also uncovered counterparts of specimens that had been collected by earlier expeditions, including a
specimen of Branchiocaris pretiosa (which turned out to match a fossil that had been
collected by Percy Raymond in 1930, 45 years earlier!). The Cambridge group
took advantage of the 1975 collection, including several ROM specimens in their publications.

The finding of a few rare and new fossils (including some from above the Raymond and Walcott Quarries) indicated there could be entirely new fossil layers waiting to be excavated - a prediction confirmed just a few years later. Taken together, all these discoveries demonstrated new field work and collections in the area could still produce valuable research material.

The reconnaissance years (1981-1989)

Starting in 1981 and for a total of six field seasons (1981-1984, 1988, 1989), the main goal of the ROM Burgess Shale parties was finding new Burgess Shale sites in the Stephen Formation. During the early stages (particularly 1981-1982) few fossils were collected, but the rate of discovery would increase in the following years, thanks largely to excavations of the new sites.

Key Geological Studies

The ROM parties were inspired by the detailed geological work of Ian McIlreath, who had been working on his Ph.D. at the University of Calgary on rock formations related to the Burgess Shale in the mid 1970s. McIlreath had made a key discovery. He recognized that the submarine cliff adjacent to the Walcott and Raymond Quarries on Fossil Ridge (defined by Fritz in 1966 and originally spotted by Ney in 1954 on Mount Field) persisted for more than 20 kilometres (12.4 miles), running through several mountains across Yoho National Park in a roughly northwest-southeast direction. If the submarine cliff (referred to as the Cathedral Escarpment) was important in the formation and preservation of Burgess Shale fossils in the adjacent basinal Stephen Formation (as suggested by earlier GSC studies), then more discoveries were probably waiting to be made elsewhere along it.

Discovery of New Sites

The ROM crew's discovery of rare fossils above the Walcott and Raymond Quarries in 1975 suggested there should be more fossil deposits present somewhere in the area. But Parks Canada would not allow any new excavations above the fossil localities prior to 1984. In 1981 Collins was accompanied by Derek Briggs (who returned in 1982) and Simon Conway Morris. (Both researchers had just completed their doctoral studies on the Burgess Shale fossils.)

Simon Conway Morris (left) and Derek Briggs (right) at Walcott Quarry, with Emerald Lake in the background, July 12, 1981.

In most cases, only a few fossils were collected from each location, and only from talus material, so the stratigraphic origin of the fossils was difficult to determine. But at a few sites, fossils were also extracted from in-situ layers of rock, giving a better understanding of their stratigraphic relationship to the rock layers at the other sites.

Some of the new localities came from rock layers that were older than the rocks of the original Walcott Quarry, while other localities came from rock layers that were younger (see How Old is the Burgess Shale). This suggested the Burgess Shale biota not only spread out over a broad area, but also survived over a longer time span than originally thought.

Two of the new sites discovered by the ROM during these reconnaissance years were particularly remarkable and would be extensively excavated in coming years.

One of the first new localities discovered in 1981 was on Mount Stephen not too far from the Trilobite Beds featuring spectacular new specimens of Branchiocaris. It was originally dubbed W.S. for "West Stephen" but is now known as the Collins Quarry on Mount Stephen.

Derek Briggs discovers a Branchiocaris specimen at a new locality on Mount Stephen (now called the Collins Quarry on Mount Stephen), July 1981.

In 1982 the ROM parties started to excavate blocks of rock from this site, providing many specimens of Alalcomenaeus and Branchiocaris as well as new animals, such as the ctenophore Xanioascus. (Alalcomenaeus and Branchiocaris are very rare in the Walcott and Raymond Quarries but proved surprisingly abundant in the Collins Quarry on Mount Stephen.)

Same location as above, David Rudkin poses with fossil of a new animal, now described as Xanioascus, on July 6, 1982.

The first significant excavation of this new site took place in 1983. Because of the steep location, a helicopter had to airlift wooden platforms for tents to the site of the base camp. Out of the remarkable fossils discovered at the locality, one arthropod was perhaps the most striking. Originally thought to be a possible distant relative of modern spiders, it was quickly nicknamed "Santa Claws" (now known as Sanctacaris) for its many pairs of spined appendages.

Sanctacaris uncata (part and counterpart) from the Collins Quarry on Mount Stephen discovered by ROM crew in 1983, except the posterior part of the counterpart (bottom right) which was discovered in 2007 in loose rocks below the site.

The 1983 expedition included Chen Jun-Yuan, a colleague of Desmond Collins who, like Collins, had trained as a specialist in cephalopods. Coincidentally, it was the very next year that Chen's colleague, Hou Xian-Guang would discover the Chengjiang fossil deposit – a major deposit of Burgess Shale-type fossils in China that has become perhaps as famous as the Burgess Shale itself. Following this discovery, Chen refocused his career on studying the Chengjiang fauna, undoubtedly influenced by his earlier trip to the Burgess Shale.

Fossil specimens were collected from talus material in 1982, 65 metres (213 feet) above the Walcott Quarry, but the source of those fossils would not be discovered for two more years.

The 1984 field season included more reconnaissance work, but the highlight of that summer was the excavation of fossils above the Raymond Quarry. The ROM crew camped in the Walcott Quarry, pitching tents on top of the snow that had accumulated within the quarry, and using the snow for drinking water and to preserve food (a practice followed in subsequent years). But the Quarry proved a precarious spot to spend the night! Rocks kept sliding down the side of the mountain (sometimes dislodged from the new excavations up the slope or jostled loose by passing mountain goats) and crashing into the tents in the quarry below. Excavations from this locality continued for another eight weeks in 1988.

Discovery of the Ehmaniella Zone layer above the Raymond Quarry by David Rudkin, July 13, 1984.

During these two field seasons (1984 and 1988), two quarries were started at two different levels separated by a stratigraphic interval of about 5 metres (16.4 feet). The quarries were given ROM field names "EZ" and "UE" for Ehmaniella Zone and Upper Ehmaniella, named for the abundant trilobite present in both localities. "UE" was the higher and became the larger of the two quarries. (Both are now referred to as the Collins Quarry on Fossil Ridge.) They became a valuable source for new specimens of previously rare animals - a critical resource for researchers as they started reinvestigating these animals.

Among many other finds, the two new quarries yielded abundant specimens of:

the vermiform animal Banffia (previously known from only two specimens and now reinterpreted as a member of a problematic group of organisms called the vetulicolids),

articulated specimens of Hurdia (allowing the animal to be reinterpreted as a smaller relative of the largest predator known in the Cambrian, Anomalocaris), and

the puzzling Nectocaris (previously known from a single specimen and now reinterpreted as a primitive cephalopod).

In 1983, the ROM team discovered a new fossil site on Mount Stephen (dubbed "S7" and known today as the "Tulip Beds - S7"), further east from the Sanctacaris locality. It did not appear to be much of a discovery at the time, producing only a few bits of specimens.

The ROM returned to this locality in 1989, a field season which was mostly given over to reconnaissance, looking for undiscovered deposits of fossils. At the "S7" locality, the ROM crew discovered many "Tulip-like" fossils, which represented a completely new type of animal.

This locality has since provided thousands of specimens, including several species that have yet to be described.

Talus slope below the "Tulip Beds (S7)" with Mount Field in the background.

Unlike previous excavations on Fossil Ridge (by Walcott and Raymond), the ROM crews took great care to record the exact layers from which each specimen was collected. This was also an improvement over the previous GSC collecting methods, which consisted of recording the location where fossils were found measured from particular intervals. Each GSC interval usually represented various layers, so it was impossible to relate a specimen to a particular layer.

Knowing the precise levels at which the specimens were collected has allowed detailed taphonomic and paleoecological studies that were impossible using previous collections.

The Collins Quarry

The 1990 ROM expedition was much larger than in previous years, kicking off a decade of extensive digs. (The only exception was 1996, which was dedicated partially to reconnaissance.) Large crews worked the sites for up to two months each summer, with additional grants from National Geographic and Parks Canada supplementing the funding provided by the ROM since 1975.

In addition to continuing excavation in the Collins Quarry on Fossil Ridge (previously known as UE and EZ), a particularly rich layer of Tuzoia specimens was discovered between the Collins and Raymond Quarries - something hoped for since the 1975 expedition. This discovery further demonstrated that Burgess Shale fossils occur through almost the entire Stephen Formation succession on Fossil Ridge, but with very different compositions of fossils in different layers.

Work in the Collins Quarry (top) and general view of Fossil Ridge (bottom) showing the location of the Collins Quarry (upper left), and the ROM campsite (lower right) in the Walcott Quarry.

In 1990 the ROM crews also began to host official guided tours of the localities as part of an agreement with Parks Canada. (Guided tours of the area are still available from Parks Canada). Because of dangerous rock falls in previous seasons the ROM crew moved its campsite out of the Walcott Quarry in 1990 to a more secure meadow near the base of Fossil Ridge. This was the same campsite used by the GSC during the 1966-1967 expeditions, and by the first ROM crew in 1975.

ROM camp in the Walcott Quarry (top) and below Fossil Ridge (bottom) after being relocated for safety reasons.

From 1991 to 1993 (and again during part of 1997) the major goal was re-excavating layers at the level of the original Raymond Quarry, which proved to be far more productive than the layers above in the Collins Quarry. The ROM started several excavations northwest and southeast of Raymond's original quarry and after a few years of excavations, the three small quarries merged into one large quarry. As was the case for all previous excavations, the work was done mainly by hand — using sledge hammers and chisels to split the rock (with occasional recourse to rock saws and a gas-driven jackhammer-drill).

Work at the level of the original Raymond Quarry with a group of tourists.

Over the course of the four seasons in the Raymond Quarry, nearly 5,000 specimens were collected. Many important fossils were discovered during this period, including some representing entirely new forms, like the tentaculate animal Herpetogaster.

But the research highlight of 1991 was almost certainly the discovery of the most complete Anomalocaris specimen ever found. This was duly (if modestly) referenced in Collins' field notes:

"Aug 27 (Tues) Crew up in quarry by 10. Catalogue large slabs. Parks tour including Bruce Runnegar arrives at 2. Catalogue now up to 1415 – whole Anomolocaris canadensis."

While the nature of this species as a predator had been determined earlier by Whittington, the quality of the complete specimen (as well as additional ones collected by the ROM) provided new anatomical details and previously-unknown morphological features, confirming its status as a large, swimming predator.

The most complete Anomalocaris canadensis ever found was collected in 1991 in the Raymond Quarry. (Part and counterpart).

After nearly two decades of searching for new sites, scouring talus slopes on different mountains through Yoho and Kootenay National Parks, and excavating new fossil layers closer and closer to the Walcott Quarry, the ROM team was given permission to re-open the famous site.
In 1994 and 1995 the ROM team turned almost all its resources to the Walcott Quarry, where major excavations would not end until 2000. This latest phase had started with trial pits dug in 1992 (and again in 1993) below the original Walcott Quarry floor. The ROM crews were astonished to find very fine, soft-bodied fossils in layers that Walcott had rejected almost 80 years earlier as incapable of preserving fossils. (ROM crews had spent several seasons camping in this quarry, little realizing as they spread out their bedding that they were sleeping on a cache of valuable fossils.)

The Walcott Quarry at the beginning of the 1994 field season (top), end of 1994 season (middle), and end of the 1995 field season (bottom).

Before reaching these new levels, the task ahead of the ROM crew at the beginning of the 1994 field season seemed nearly insurmountable. First, the huge quantity of snow accumulated in the Quarry during the past winter had to be shoveled away. When the team arrived at the site in early July, they found three distinct patches of snow filling the Walcott Quarry, the Raymond Quarry, and the Collins Quarry. (Ironically, it was the excavations from previous years that led to the problem as the deep holes proved ideal for keeping the snow frozen, even in the middle of summer.) Once the snow was removed, the heavy work began. With a team of eight, it took the better part of both collecting seasons (two months in total) just to remove the rock debris that had accumulated since Walcott's time.

Fossil Ridge with snow showing the locations (from top to bottom) of the Collins, Raymond and Walcott Quarries.

The work was split between removing the debris and quarrying the floor of the Walcott Quarry in search of fossils. During the clean-up, the ROM team uncovered rusted tools and a frozen block of newspapers dating from 1913 to 1917 (which Walcott had apparently brought to the area for wrapping fossils.)

Removing snow and debris that had accumulated in the Walcott Quarry, view to the north (top) and to the south (bottom).

The effort paid off, and in the remainder of the collecting seasons, with the team carefully collecting fossils layer by layer, they recovered at least 10,000 specimens from just two rock layers located approximately 1.2 and 1.3 meters (4 feet) below Walcott's Quarry. As was the case in the rest of the Phyllopod Bed, Marrella splendens was the most common fossil, but there were also many specimens of previously rare species including Pikaia gracilens and Hallucigenia sparsa.

From 1997 to 2000 the ROM crews spent each summer excavating layers of rock in the Walcott Quarry. (The crews also collected material from several previously-excavated sites such as the Tulip Beds (S7) locality on Mount Stephen, but the main focus of those years was excavating the Walcott Quarry, layer by layer.)

Excavating fossil layers below the original floor of the Walcott Quarry, Mount Burgess in the distance, 1999.

Among the student volunteers who joined the expedition from 1998 to 2000 was Jean-Bernard Caron, who today is Curator of Invertebrate Palaeontology at the Royal Ontario Museum. He succeeded Desmond Collins, who retired in 2005.

Jean-Bernard Caron (left) and Desmond Collins (right) below the Walcott Quarry at the end of the 2000 ROM expedition.

In 2000, with the excavations reaching about 5 metres (16.4 feet) below the floor of the original Walcott Quarry, the fossil-bearing layers suddenly stopped. At this depth, a different type of rock (the Wash Limestone Member) was encountered which did not yield any soft-bodied fossils. At greater depths, the rock layers were increasingly deformed by numerous faults, greatly reducing the surface area available for excavation.

Panorama of the Walcott Quarry at the end of the 2000 ROM expedition showing the maximum extent of the excavation.

The accumulation of snow in the quarry was also a growing problem as the quarry grew deeper each year. In 1999, the ROM crew had to spend almost a month (half of the field season) removing the snow that had piled up in the quarry before the actual work of excavation could begin.

During these later expeditions, dozens of fossiliferous layers were systematically excavated by the ROM crews, with some bearing forms that had previously been extremely rare. A particular example was the bizarre animal Odontogriphus omalus, which had originally been described based on a single specimen. The ROM party discovered almost two hundred additional fossils of the animal, enabling a complete re-interpretation of what it originally looked like (published in Nature and exhibited at the ROM in 2006) suggesting the animal was probably related to a very ancient stock of mollusk. The lower levels also produced new species, including another mollusk-like animal called Orthrozanclus reburrus (fossils of which had been known to Walcott, but remained undescribed).

Summary of the ROM Burgess Shale expeditions under Desmond Collins

The 18 years of field work by ROM teams under Collins brought a vast increase in our understanding of the Burgess Shale's fauna, structure, and diversity, as well as its distribution in space and over time. Today, the ROM holds the largest collection of Burgess Shale fossils in the world (more than 150,000 specimens), containing examples from all major beds and many new sites. These specimens will continue to be a valuable resource for the foreseeable future as new discoveries are uncovered not only in the field, but in the existing collection of fossils.

Solid line represents the limit of the ROM excavations still visible today on Fossil Ridge. Dashed lines represent excavation limits by other groups. The Raymond and Walcott Quarries were dramatically extended by ROM crews.

Current ROM Field Work-Based Research Activities

New Explorations and New Discoveries

In 2006, Jean-Bernard Caron joined the ROM after completing a study on the animal Banffia constricta for his M.Sc. and a Ph.D. on the taphonomy and ecology of the Walcott Quarry community. His appointment shifted the focus of the ROM expeditions from large excavations (collecting a large number of fossils) to a smaller-scale program of reconnaissance and exploration, combined with continuing studies of existing fossil collections. Since 2008, the focus has been on integrating all available information found in the field (micro and macrofossils, sediment, and trace fossils) using an interdisciplinary and collaborative approach. The current objective is to study areas that are known to be sources of Burgess Shale-type fossils but which have not yet had their fossil content or geology studied extensively.

Jean-Bernard Caron (right) with David Attenborough in the Walcott Quarry.

The ROM 2008 Burgess Shale Expedition

The first site to be studied under this new research framework was a locality discovered in 1988 near the Stanley Glacier, 30 kilometres (18.6 miles) south of the main Burgess Shale site.

The talus slopes in the Stanley Glacier area had been visited by ROM crews before (in 1989 and 1996) but the geology of the area had not been studied in any detail, and the origin of the fossils remained unknown. The number of fossils from the area (prior to the 2008 expedition) was also too limited to allow comparisons with other Burgess Shale-type deposits. To address these deficiencies, a three-week expedition to the Stanley Glacier area was organized in the summer of 2008.

The 2008 ROM Burgess Shale crew at the main Stanley Glacier site - August 2008. Left to right, Jean-Bernard Caron, Allison Daley, Robert Gaines, Michael Streng and Jason Loxton.

The team discovered the original source of fossils previously collected from the talus slopes by doing small excavations of in-situ rock blocks. They were then able to trace the thin strata for several kilometres, showing the fossiliferous outcrops were widely spread geographically and confirming they were part of the "thin" Stephen Formation (an idea which had been previously hypothesized, but not proven). Advances in technology made it possible to map and record the exact location of the fossil sites using digital photography and GPS coordinates.

Crew and Parks Canada staff working at the main Stanley Glacier site - August 2008.

The team was able to reveal that the Stanley Glacier site represented a very different environment, with no escarpment immediately adjacent to the sites - in contrast to all previous Burgess Shale-type deposits in the Canadian Rockies. Despite the short duration of the field work and relatively small number of specimens studied (around 1,000), new species were discovered along with known species.

The 2008 ROM expedition demonstrated there are still new Burgess Shale-type fossils to be discovered more than one hundred and twenty years after the first fossils on Mount Stephen were discovered.

A new ROM expedition set out in the summer of 2010, with a particular focus on determining more precisely the stratigraphic position of several poorly known fossil localities on Mount Stephen and Mount Odaray. These sites were discovered in 1981 by the ROM but had not been studied in detail since. More expeditions are planned to areas that might represent paleoenvironmental settings different from that of the classic Burgess Shale.